The Australian Automobile Association, which claims 7 million members via its state auto clubs, has called on Australian governments to spend $100 billion on better transport infrastructure. The AAA published a priority list of five transport projects in each state (there are only four in South Australia and one in the Northern Territory). These are regional as well as urban projects.

Although the program is titled “Demand Better Roads” and the headline is “What motorists want”, three of the 30 proposed projects are urban public transport improvements. They don’t rank highly, though — Melbourne’s Metro rail tunnel and Brisbane’s Cross River Rail are ranked third (of five) in their respective states, and Perth’s proposed light rail system is ranked fifth. There are no public transport projects proposed for NSW or other states.

The AAA ranks $16 billion to $18 billion of road projects in Victoria and $17.7 billion in Queensland ahead of the rail projects. Given the scarcity of public sector capital, that leaves little room for realistically funding public transport — this is clearly a roads program, as advertised.

The problem with a “roads only” approach is it ignores the recent strong growth in public transport patronage in most cities. It also ignores structural changes in the economy driving greater demand for employment density, especially in the central city. The argument in support of the Melbourne Metro is that the continuing growth of the CBD can’t be sustained unless the capacity of the rail system — which is approaching its limits — is increased. There’s more at stake than just reducing travel times.

There’s no doubt cars are important in our cities and will be a fact of urban life for many years yet. At present they account for around 90% of all motorised travel across Australia’s capital cities. It’s higher in Sydney and Melbourne and lower in the other capitals. Moreover, the great bulk of destinations and dwellings are in dispersed suburban locations that are far easier to serve by car than public transport. Employment and education are the prime markets for transit but most jobs and schools are dispersed too.

But governments don’t have to build new freeways. Peak period congestion can and should be moderated by congestion pricing — that is, if a trip isn’t worth paying for travellers won’t make it.

Freeways get congested because, unlike other basic services like power, water and public transport, motorists don’t “see” the cost they’re imposing on other road users. As with any scarce commodity, demand that’s under-priced will exceed capacity.

Obviating or delaying the need for new freeways would free up public capital for investing in other purposes, such as worthwhile public transport projects (I say “worthwhile” because public transport investment is at least as prone to boondoggles as roads).

But congestion pricing is politically difficult, so it makes sense to understand better why there’s an apparent push towards investment in roads and away from public transport.

Unlike roads, public transport relies on the public sector for all its capital funding. Moreover, since it only meets circa one third of its operating costs, it imposes a significant ongoing cost on state budgets.

Also, as noted above, the vast bulk of travel in Australian cities is done by car. Indeed, a recent ABS survey found only a third of adult Melburnians say they use public transport at least once a month. There are simply a lot more car users than public transport users. In what appears to be an emerging new political climate, making the case for more investment in public transport can’t rely solely on standard arguments that in some instances might not even be seen as legitimate by those holding the purse strings.

Part of the new thinking has to embrace congestion pricing and new ways that public transport can generate more revenue.